1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly to a plasma display panel that is adaptive for improving color temperature.
2. Description of the Related Art
A plasma display panel (hereinafter, PDP) is a display device using that visible ray is generated from phosphorus when vacuum ultraviolet ray generated by gas discharge excites the phosphorus.
The PDP has an advantage that it is thinner and lighter than a cathode ray tube CRT, and it can be made into a high definition large-scaled screen. The PDP includes a plurality of discharge cells arranged in a matrix, and each discharge cell becomes a pixel of a screen.
Referring to FIGS. 1 and 2, a discharge cell of a three AC surface discharge PDP in the related art includes a scan-sustain electrode 4Y and a common sustain electrode 4Z formed on an upper substrate 16, an address electrode 2X formed on a lower substrate 14. Herein, each of the sustain electrode pair 4Y and 4Z consist of a transparent electrode 4a and a bus electrode 4b. 
There are deposited an upper dielectric layer 12 and a passivation film 10 on the upper substrate 16 where the scan-sustain electrode 4Y and the common sustain electrode 4Z. The upper dielectric layer 12 is formed in a multi-layer structure, e.g., there are formed a first and a second upper dielectric layer 12A and 12B. Wall charges generated upon a plasma discharge are accumulated on the upper dielectric layer 12.
The passivation film 10 prevents the damage of the upper dielectric layer 12 caused by a sputtering that is generated upon plasma discharge and at the same time the discharge efficiency of secondary electron. The passivation film 10 is generally magnesium oxide MgO.
There are formed a lower dielectric layer 18 and barrier ribs 8 on the lower substrate 14 provided with the address electrode 2X, and the surface of the lower dielectric layer 18 and the barrier ribs 8 is coated with a phosphorus layer 6. The address electrode 2X is formed crossing the scan-sustain electrode 4Y and common sustain electrode 4Z.
The barrier ribs 8 are formed parallel to the address electrode 2X to prevent the ultraviolet ray and visible ray generated by the discharge from being leaked to adjacent discharge cells.
The phosphorus layer 6 is formed on the barrier ribs 8 and the lower dielectric layer 18, and gets excited by the ultraviolet ray generated upon the plasma discharge to generate any one of red, green and blue visible rays R, G and B.
There is injected an inert gas for gas discharge into a discharge space provided between the upper substrate 16, the lower substrate 14 and the barrier ribs 8.
In the PDP, there is formed a light-shielding layer 20 between the first upper dielectric layer 12A and the second dielectric layer 12B along the barrier ribs 8 in a direction of crossing the sustain electrode pair 4Y and 4Z in order to minimize the interference between adjacent discharge cells and to improve the contrast of a screen at the same time. Or, there is formed a light-shielding layer 22, as shown in FIG. 3, between the scan-sustain electrode 4Y and the common sustain electrode 4Z, which are formed in each of the discharge cells adjacent to each other, in a direction of crossing the barrier ribs 8.
The discharge cell with such a structure is selected by the opposite discharge between the address electrode 2X and the scan-sustain electrode 4Y, then sustains the discharge by a surface discharge between the sustain electrode pair 4Y and 4Z. In the discharge cell, the ultraviolet ray generated upon the sustain discharge causes the phosphorus 6 to emit the visible light to the outside of the cell, thereby displaying a picture.
The related art PDP have discharge cells realizing red, green and blue of a specific width with the barrier ribs 8 therebetween. The luminescent brightness of the discharge cells, which realize red R, green G and blue B, is different due to the luminescent characteristic of the phosphorus layer 6 of red R, green G and blue B, which are different from each other. Specifically, the luminescent brightness of the discharge cell, which realizes green G, is higher than those of the discharge cells, which realize red R and blue B, and the luminescent brightness of the discharge cell, which realizes red R, is higher than that of the discharge cell, which realizes and blue B. In this case, there is a problem that the color temperature of the PDP on the whole is lowered due to the low luminescent brightness of the discharge cell, which realizes blue B.
In order to solve the problem like this, the PDP with asymmetric barrier rib structure is proposed as shown in FIG. 4.
Referring to FIG. 4, the PDP with asymmetric barrier rib 26 structure has a discharge cell 28R realizing red R, a discharge cell 28G realizing green G and a discharge cell 28B realizing blue B formed to have different width from one another, thereby controlling the color temperature. In other words, the area of the discharge cell 28B realizing blue B, the luminescent brightness of which is the lowest, is formed to be the biggest, and the area of the discharge cell 28R of red R, the influence of which is the lowest on the whole brightness and color temperature, is formed to be the smallest. For example, the ratio of the area of red, green and blue discharge cells 28G, 28G and 28B is 0.8:1:2.2.
However, when coating the red, green and blue discharge cells 28R, 28G and 28B of different width, the mask and process condition for phosphorus coating get different by red, green and blue discharge cells 28R, 28G and 28B to make the operation difficult.